A filter sock is a fabric bag on a plastic ring that sits under the drain of a sump or overflow and catches debris before it reaches the rest of the system. Socks differ in micron size, ring diameter, length and fabric, and most are described as reusable after rinsing.
The six options below range from a two pack of felt socks to a sixteen pack and a set that includes an acrylic holder. Dimensions, micron sizes and materials come from each Amazon.com listing. We have not used these products ourselves. Filtration claims are the makers’ own.
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What to Look For
| Feature | Why it matters |
|---|---|
| Micron size | A lower number means a finer weave; listings show 150 or 200 |
| Ring diameter | It must match your holder or filter cup |
| Length | Longer socks hold more debris |
| Fabric | Felt, nylon, polypropylene and mesh all appear |
| Pack size | A bigger pack allows swapping while others dry |
Specs at a Glance
| Filter sock | Size | Micron | Notes |
|---|---|---|---|
| Aquatic Experts | 4 x 14 in; 2 pack | 200 | Polyester felt; molded plastic ring |
| XUANZIKEMAO | 4 in ring; about 9.8 in long; 12 pack | 150 | Honeycomb woven mesh |
| Oudain | 4 x 14 in; 16 pack | 200 | White; plastic ring about 4 in |
| Tranqun | 7 x 4.5 in rectangle; 4 pack | 200 | White; polypropylene and plastic |
| Ninehaoou | 4 in ring; 8 socks plus holder | 200 | Nylon socks; acrylic holder |
| Conloquen | 7 in diameter with 4 in ring; 14 in long; 8 pack | 150 | Non-woven 3D honeycomb |
The 6 Best Aquarium Filter Socks
1. Aquatic Experts Felt Filter Socks, 4 Inch Ring, 200 Micron
A two pack of 4 by 14 inch socks made from polyester felt with a molded plastic ring that fits standard filter cups and holders. The listing says they are reusable and are not compatible with Red Sea filter trays.
Suits: a standard 4 inch holder. Strengths: a dense felt and a clear fit note. Weaknesses: only two in the pack. Skip it if you want many spares.
View Aquatic Experts Felt Filter Socks 4 Inch 200 Micron on Amazon
2. XUANZIKEMAO 12 Pack 4 Inch Honeycomb Filter Socks
Twelve ring-style socks about 9.8 inches long with a 4 inch diameter and a 150 micron size. The listing describes a woven mesh with a honeycomb design.
Suits: a rotation of spares. Strengths: twelve in the pack and a finer weave. Weaknesses: shorter than the 14 inch socks. Skip it if you want a longer sock.
View XUANZIKEMAO 12 Pack 4 Inch Honeycomb Filter Socks on Amazon
3. Oudain 16 Pack 4 Inch Filter Socks, 200 Micron
Sixteen white socks about 14 by 4 inches, each with a plastic ring of roughly 4 inches. The listing names polypropylene yet also describes interlocking micro felt fibers, so confirm the fabric with the seller.
Suits: a large stock of spares. Strengths: the largest pack here. Weaknesses: conflicting fabric wording. Skip it if you need to know the exact material.
View Oudain 16 Pack 4 Inch Filter Socks 200 Micron on Amazon
4. Tranqun 4 Pack Rectangle Filter Socks
Four white socks in a rectangular shape measuring about 7 by 4.5 inches with a 200 micron size, made from polypropylene and plastic. The listing calls them washable and reusable.
Suits: a rectangular opening. Strengths: a different shape from the rest. Weaknesses: not a ring style. Skip it if your holder takes a round ring.
View Tranqun 4 Pack Rectangle Filter Socks 200 Micron on Amazon
5. Ninehaoou 8 Pack 4 Inch Filter Socks with Holder
A bundle of one 4 inch pre-sump holder and eight 200 micron nylon socks. The acrylic holder has pre-drilled mounting holes and polished edges according to the maker.
Suits: a first setup without a holder. Strengths: a holder in the box. Weaknesses: you must match your sump layout. Skip it if you already own a holder.
View Ninehaoou 8 Pack 4 Inch Filter Socks with Holder on Amazon
6. Conloquen 8 Pack 7 Inch Honeycomb Filter Socks
Eight 150 micron non-woven 3D honeycomb socks, each 7 inches in diameter with a 4 inch ring and 14 inches long. The title says 7 inch, so the ring is still 4 inches.
Suits: a larger capacity sock on a 4 inch ring. Strengths: a wide body and fine weave. Weaknesses: the 7 inch title can mislead. Skip it if you need a slim sock.
View Conloquen 8 Pack 7 Inch Honeycomb Filter Socks 150 Micron on Amazon
Specs to Check Before Ordering
- The ring diameter of your holder.
- The micron size you want.
- The sock length against your sump space.
- The fabric named in the listing.
- The maker’s cleaning instructions.
Mistakes to Avoid
- Confusing sock diameter with ring diameter.
- Ordering a rectangle sock for a ring holder.
- Ignoring fit notes such as the Red Sea tray remark.
- Buying a pack size that does not match how many you need.
Aquarium Filter Sock FAQ
What does 200 micron mean?
It is the weave size given by the maker. 150 micron socks are listed as finer than 200 micron ones.
Are they reusable?
The Aquatic Experts, Tranqun and Ninehaoou listings call them reusable or washable. Follow the maker’s cleaning instructions.
The Short Version
For felt, the Aquatic Experts. For spares, the XUANZIKEMAO. For the largest pack, the Oudain. For a rectangle, the Tranqun. For a holder in the box, the Ninehaoou. For a wider body, the Conloquen.